In motor vehicle seats, generally the backrest is able to be adjusted as finely as possible within a predetermined angular range at different angular positions, this adjustment being denoted as the backrest tilt adjustment. In motor vehicles with only one door per vehicle side and with rear seats or in vehicles with a third seat row, entry into a rear seat is facilitated by the backrest of the front seat being able to be folded forward rapidly. Folding forward the backrest of a rear seat is also desired for providing an enlarged loading base which is as flat as possible.
One problem with such adjusting devices is that they often have to be fitted in locations which have a small amount of installation space. Frequently, operating levers are concealed, also due to the construction, and/or arranged so as to be accessible only with difficulty by the user. To this end, in conventional adjusting devices a manual tilt adjustment of the backrest is generally complex and awkward for the user.
A vehicle seat comprising a generic adjusting device is disclosed, for example, in DE 10 2005 052 201 A1. The vehicle seat has a seat frame and a backrest which is able to be pivoted and folded relative to the seat frame, wherein in its locked use position the tilt of the backrest is able to be adjusted by motor within a comfort range into a plurality of comfort positions and, after being unlocked, the backrest (4) is able to be folded by motor between the upright use position and a folded-forward cargo position with a substantially horizontal position of the backrest. Moreover, a motorized drive is provided in the backrest, wherein a first electromotive adjusting device which is fixed to the backrest is provided for the tilt adjustment of the backrest and a second electromotive adjusting device which is fixed to the backrest and which is different from the first adjusting device is provided for folding the backrest. A common backrest pivot axis is provided for the pivoting movement of the tilt adjustment and the folding movement for folding the backrest, wherein the drive axes of the first and second electromotive adjusting device are different and a transmission means is provided.
A seat device comprising a rotary transmission mechanism is disclosed in US 2011/0 095 584 A1, said rotary transmission mechanism providing the transmission of the rotation to each of a plurality of adjusting mechanisms. This rotary transmission mechanism encompasses a motor, a worm, and two worm wheels in each case meshing with the worm and arranged in the vicinity of one another. This rotary transmission mechanism contains four clutch members, the clutch elements thereof being correspondingly arranged between the adjusting devices and the worm wheels. Each clutch element is configured such that it is able to be switched between a transmission state and an interruption state.
A gear set for a vehicle seat adjusting device is disclosed in DE 10 2007 061 902 B3, wherein the gear set comprises a drive pinion which is able to be driven by a motor shaft of an electric motor and an output gearwheel. It is also provided that an intermediate gearwheel unit is provided with a first intermediate gearwheel which is in engagement with the output gearwheel, wherein the drive pinion is able to be adjusted in the axial direction of the motor shaft between a first position in which it is in engagement with the intermediate gearwheel unit and a second position in which it is directly in engagement with the output gearwheel, wherein in the first and second position the output gearwheel is driven by the motor shaft with different reduction gear ratios.
Further generic vehicle seats are disclosed, for example, in DE 103 56 614 A1 and DE 10 2012 008 533 B4.